1. Field of the Invention
The invention is in the field of linearly actuated control devices which are directly actuated, or indirectly actuated by means of Bowden cables, and used, for example, in switching, regulating or steering devices.
2. Description of the Prior Art
A known device of the prior art consists of a take-up body which is supported in a circular, closed housing and actuated by means of an outwardly protruding axle. The device has a flexible tension and compression element which is fastened on one end to the take-up body and guided within in an annular shape formed between the take-up body and the housing and within a tube which extends tangentially outwardly from the annular space. In this known device, the take-up body is formed by a ratchet wheel, and the flexible tension and compression element comprises a flexible wire carrying spherical bodies fastened on the wire at distances corresponding to the distribution of the teeth of the ratchet wheel, so that the spheres are located in the circular recesses formed by the teeth.
A disadvantage of this prior art device is that it is limited in transmitting compressive forces to a value determined by the flexural rigidity of the wire insert which is a relatively low value. If this value is exceeded, the tension and compression element will buckle in the runout zone not supported by the ratchet wheel, namely, at points between the spherical elements, thus leading to the destruction of the entire actuating device.
A further disadvantage of this prior art device consists of the fact that the flexibility of the tension and compression element is strongly affected by the stationary connection of the spherical elements which is functionally necessary for operation of the device. This fixed connection of the spherical elements blocks approximately three-fourths of the overall length of the tension and compression element, so that these parts do not participate in the bending of the element. This arrangement sets a natural lower limit of the dimensions of the actuating device.